Most drugs conventionally used to treat ophthalmic disorders have potentially serious side effects such as blurring of vision and other visual side effects which may lead either to decreased patient compliance or to the termination of therapy. Occasionally systemically administered drugs can also cause serious side effects, such as nausea, dyspepsia, fatigue, and metabolic acidosis, which affect patient compliance and/or necessitate the termination of treatment. Additionally, some β-adrenergic antagonists have increasingly become associated with serious pulmonary side effects attributable to their effects on β-2 receptors in pulmonary tissue. Hence there is a need in the art for compounds that have improved efficacy, lower toxicity and/or fewer side effects and that can be used at low dosages. The invention is directed to these, as well as other, important ends.